Driving connection



July 7, 1942. H. VON TAVEL DRIVING CONNECTION 4 Sheets-Sheet 1 FiledOct. 29 1941 wwwwww July 7, 1942. H. VON TAVEL 2,288,963

DRIVING CONNECTION Filed Oct; 29, 1941 4 Sheets-Sheet 2 Fig.5

July 7, 1942. VON TAVEL 2,288,963

DRIVING CONNECTION Filed 001:. 29, 1941 4 Sheets-Sheet 5 K ll/Ill July7, 1942. H. VON TAVEL 2,288,963

DRIVING CONNECTION Filed Oct. 29, 1941 4 Sheets-Sheet 4 aa mbm 215gPatented July 7, 1942 Application October 29, 1941, Serial No. 417,040In Switzerland August 27, 1940 3 Claims.

Th present invention relates to a driving connection adapted to operatea rectilinearly reciprocable member by means of a shaft revolving on anaxis or the like. Moreparticularly, the invention is concerned with animproved driving connection "between the reciprocable piston and thepower driven revolving shaft of a plunger machine, saidrevolvingshaftcarrying an eccentric on which revolves with the sameangular speed in the oposite direction a second eccentric having thesame eccentricity and being supported in the reciprocable member.

In known driving connections of this class both eccentrics are formed bycrank pins, and the crank associated with the pin which provides thesecond eccentric is connected to a gear wheel rolling on a stationaryinternally toothed gear ring, the diameter of the pitch circle of saidgear ring being twice the diameter of the gear wheel. The eccentricityof each of the crank pins must therefore equal the radius of the pitchcircle of the gear wheel. But the radius of said circle has a minimumlength which is determined by the required mechanical resistance and theconditions of engagement, and the above construction is, therefore, notadapted for drives wherein the reciprocable member operates with smallthrows as compared with the amount of eiforts to be transmitted.

It is an object of the invention to greatly simplify and cheapen theconstruction of such driving connections as well as to secure greaterreliability of performance and an economy of space, by employingeccentrics instead of crank pins as heretofore.

Another object of the invention is to provide means for so coupling themovable parts of the driving connection as to adapt said'connection todrives operating with a relatively small throw of the reciprocablemember while transmitting rather high efforts to or from said member.

With these objects in view, the invention resides in those novelfeatures of construction, combination and arrangements of parts whichwill be hereinafter first fully described, and then be specificallypointed out in the appended claims, reference being had to theaccompanying drawings, illustrating, by Way of example, two preferredembodiments of the invention.

In the drawings:

Fig. 1 is "a longitudinal section taken on the lines AA in Fig. 2. of adriving connection according to the first embodiment of the invention.

Fig. 2 is a cross sectional view taken on the line 3-3 in Fig. 1 andFig. 3 is a horizontal section taken on the line CC in Fig. 1; Figs. 4and 5 are cross sectional views taken respectively on the lines DD andE-E in Fig. 1 showing the same driving connection.

Fig. 6 is a cross sectional view taken on the line F-F in Fig. 1 showinga part of the said driving connection.

The Figs. '7 to 11 represent each schematically a sectional view ofessential parts of the said driving connection in different positions.

Fig. 12 is a longitudinal section taken on the line GG in Fig. 13,showing a driving connection according to the second embodiment of theinvention.

Fig. 13 is a cross sectional view taken on the line HH in Fig. 12 ofthis second embodiment.

Fig. 14 showsa horizontal section taken on the line KK in Fig. 12 of apart of the said connection.

Figs. 15 to 18 are cross sectional views similar to Fig. 13 showing apart of the connection, the

movable members being represented in different positions.

The driving connection represented in Figs. 1 to 11, comprises 'a shaft2 turning about the axis l and supported in bearings 3 and 4. Thebearings are preferably constructed of two halfsections providedrespectively in the upper casing part 5 and the removable lower casingpart 6 of the driving connection. The shaft 2 is provided with aneccentric I formed integral therewith and having its working surface 8concentrically disposed relative toaxis 9, the latter beingspaced fromthe axis 1 at, a distance equal to the eccentricity e1.

On the working surface 8' of the eccentric l is seated a second or outereccentric Hlhaving a working surface 'I I concentric to'the axis I2; theeccentricity of the eccentric I'G, that is the distance eg between theaxes 9 and I2 of its inner and outer working surfaces, is equal to theeccentricity e1 of the inner eccentric I.

The outer eccentric I0 is held against axial displacement, on the oneside, by a collar 13 fast with the inner eccentric I and, on the otherside, by a distance sleeve l4 interposed between said eccentric and theinner end face of the bearing 4. Since the outer periphery of the flangel5 of the sleeve l4 has its center on the eccentric axis 9, the sleevemust be held against rotation on the shaft I, and this is convenientlyeffected by means of a pin l6 seated in said shaft and engaging a slotll of the sleeve.

The outer eccentric I6 is itself mounted in a solid eccentric strap l8which is shown having a pin l9 projecting into a rectilinear guide slot28 provided in the lower casing part 6.

The numeral 2| designates two pistons of a plunger machine, 1. e. apump, which are both of equal size and symmetrically disposed as to theaxis of the shaft 2. Said pistons are reciprocable and fit comparativelysnug within two cylindrical bores 22 of the upper casing part 5 whichare shown communicating with each other by means of a duct 23 in saidcasing part.

The lower end of each of the pistons is shown forming a head 24 setlaterally into a slot 25 of the eccentric strap I8, said slot having aninverted T-shaped transverse formation. There is no play between thepiston heads 24 and said slot, neither in the upward or downwarddirection nor in the direction parallel to the axis of the workingsurface II; the pistons 2| thus partake of the up-and-down movement ofthe eccentric strap and prevent said strap from axial displacement onthe working surface I I.

On the driving shaft 2, adjacent the bearing 3 is fixedly mounted abevel gear 26 by means of a key 27. Opposite this gear is mounted asecond bevel gear 28 which is freely rotatable on the shaft 2, the pitchand number of teeth of said second gear wheel being equivalent to thepitch and number of teeth of the bevel gear 26. Between the bevel gear28 and the inner eccentric I is interposed a distance sleeve 29 seatedon the shaft 2.

The bevel gears 25 and 28 are shown meshing with an intermediate bevelgear 38 which is fixedly mounted by means of a key 32 on the shaft 3|extending perpendicularly to the driving shaft 2 and supported in theupper casing part 5. A cap screw 33 prevents the bevel gear 38 fromaxial displacement.

The shaft 3| may be used for driving an auxiliary apparatus, i. e. agear pump 34 sucking liquid from a tank 35. Said gear pump comprises agear wheel 36 keyed to the shaft 3| and which meshes with a second gearwheel 31 journalled on a stud 38 extending parallel to the shaft 3| (seeFig. 3). Both said gear wheels closely fit the gear pump casing on theirside faces and over a considerable portion of their circumferences, sothat when driven, they suck liquid from the tank 35 through the supplypipe 39 into the gear pump casing and displace said liquid to a deliverychamber 4|] in said casing. From the delivery chamber 49 the liquidflows through a duct 4| in the gear pump casing into a conduit 42 andfrom there through a filter 43 into a conduit 44 leading to the duct 23of the cylindrical bores 22 in the casing part 5. Upon upward stroke ofthe pistons 2| the admission of liquid in the cylinders 22 isinterrupted and liquid is pressed through the check valves 45 into thedelivery piping 46.

The bevel gear 28, which by reason of the intermediate gear wheel 30 hasto turn with the same speed and in the opposite direction as the bevelgear 26, is rigidly coupled with the outer eccentric I8 by means of anintermediate disk 53.

The said disk has on its side facing the bevel gear 28 two squareprojections 54 disposed diametrically opposite each other and engagingwith a corresponding slot 55 extending diametrically on the backside ofthe bevel gear 28; the disk 53 is thus displaceable in this slotrelativeto the said bevel gear, perpendicularly to the axis of rotationand, at the same time, partakes of the rotation of said gear. On theside of the disk 53 looking towards the eccentric I0, there is provideda slot 56 extending along a diameter which is perpendicular to thediameter connecting the projections 54. This slot'engages twoprojections of the eccentric Ill, lying on a diameter which crosses theaxes 9 and I2 of the two working surfaces 8 and II respectively. Theeccentric I9 is thus displaceable along this diameter perpendicular tothe axis of rotation and, at the same time, partakes of the rotation ofthe disk 53. Consequently it is also coupled for rotation with the bevelgear 28, while being freely movable relative thereto in a planeperpendicular to the axis of rotation, this movement being possible ineither direction as far as required to allow for rotation of the outereccentric I8 on the inner eccentric I. The said movement generallycauses a displacement of the intermediate disk 53 relative to the bevelgear 28, and also a displacement of the eccentric I0 relative to theintermediate disk 53, said displacements being perpendicular to oneanother.

The mechanism just described is in effect an Oldham coupling which, aswell known, permits relative lateral displacement of two rotatingbodies, but constrains them to rotate at equal angular velocities.

The Figs. 7 to 11 show schematically the movable members of the drivingconnection in different positions. The arrow 58 indicates the directionof rotation of the shaft 2 and the inner eccentric 7. The outereccentric It then rotates in the opposite direction, that is in thedirection of the arrow 59 with the same angular speed relative to thestationary casing 5, 6. The arrows BI) and GI may be engraved in theeccentrics I and I8, respectively, to indicate the angular position ofthe said eccentrics.

Fig. 7 shows the movable members in the position whereby the pumppistons attain the lower limit of their stroke. The axes I, 9 and I2 arethen placed in one and the same vertical plane which is symmetrical tothe pistons 2| In the positions shown in Fig. 8 the driving shaft hasturned over angle a in the clockwise direction. The .axis 9 lies no morein the vertical plane intersecting the axis I and extendingsymmetrically to the pistons 2|. But since the angle ,8 over which theeccentric II] has turned about the axis 9 in counterclockwise directioncorresponds to the angle ac, and since the distance e1 between the axesI and 9 is equal to the distance eg between the axes 9 and I2, the axisI2 lies again in the said plane. This is the case in any angularposition of the driving shaft 2 and, consequently, the eccentric strapI9, which is concentric with the axis I2, reciprocates upon rotation ofthe shaft 2 in a rectilinear to and from movement in said vertical planethrough the axis I, which is symmetrical to the pistons 2|, therebyentraining said pistons to follow this movement.

Fig. 9 shows the axes I and I2 coinciding with one another as soon asthe angles a and p become right angles. In Fig. 10 the members are shownin a position wherein the pistons 2| have reached the upper limit oftheir stroke. The axis 9 then lies in the vertical plane intersectingthe axis I, as well as the axis I2 movable in said plane. The latter ofthe said axes is then spaced at a distance e1+e2 above the axis I while,according to Fig. 7, it was spaced at the same distance below said axis.The total throw of the pistons thus equals four times the eccentricityof one of the eccentrics.

Finally Fig. 11 shows the position during the downward stroke of thepistons, the axes I and I2 coinciding with one another.

In the embodiment shown in Figs. 12 to 18 the outer eccentric I carrieson its side facing the bevel gear I28 two pins I 42, the axes of whichare parallel to the axes I, 9 and- I2. Upon each of said pins isrockingly mounted a lever I43 having each a toothed sector I 44; thetoothed sectors I44 of the two levers are shown meshing with each otheralong pitch circle arcs of equal radius, the centers thereof lying inthe pivots of the levers. The arms of the two levers I43 remote from thetoothed sectors ltd are of equal length; they carry on their ends pinsI45 whereupon are applied steering bars Hit of equal length; theopposite end of each of said bars is pivoted on a pin I i? fast with thebevel gear I28. The two pins Iii are disposed diametrically oppositeeach other on the bevel gear and their distance is approximately equalto the mean distance separating the pins M5 on the levers hi3.

Owin to the engagement of the toothed sectors Hi l the rocking movementsof the two levers I43 relative to the eccentric Iiii! are equallyopposed to each other, that is each rocking move ment of one of thelevers causes a rocking movement of the other lever over the same anglein the opposite direction. Moreover, since the axes of the pins i 35 lieapproximately in the plane intersecting the axes of the pins I i-2, thedistance of the pins I 55 remains practically unaltered. They are, onthe one hand, displaceable relative to the bevel gear I28 in a parallelmovement to the said plane along the arcs of circle determined by thesteering bars I 66. On the other hand, owing to their distance whichremains practically constant the plane connecting their axes isdisplaced approximately parallel to itself with respect to the bevelgear. Also the plane intersecting the axes of the pins I42 may beallowed to move parallel to itself upon rocking of the levers I 33 aboutthe pins I432; this parallel displacement occurs, however, in adirection which is perpendicular to the direction of the displacement ofthe pins I45 relatively to the bevel gear I23; the pins IM and therewiththe outer eccentric it are, thus, freely displaceable, within certainlimits perpendicularly to the axis of rotation I of the driving shaft 2and, at the same time, are coupled for rotation with the bevel gear I23.The very small angular displacements which the eccentric mu may undergorelatively to the bevel gear I28 are due to the variation of thedistance between the pins I45 during displacement of the eccentric Hiand thus depend upon said variation. For the rest, the embodiment ofFigs. 12 to 18 will be the same as has been described relative to Figs.1 to 11.

In Fig. 15 the movable members are shown in a position which they assumewhen the pump pistons 2| have reached the lower limit of their stroke.Figs. 16 and 17 show these members in two positions which they occupyduring the upward stroke of the pump pistons, whereby in the positionaccording to Fig. 17 the axes I and I2 are shown coincident with eachother. Finally, in Fig. 18 the movable members are shown in the positioncorresponding to the upper limit of stroke of the pump pistons ZI.

It will be apparent from the Figures 15 to 18 that during rotation ofthe driving shaft 2 the deviation of the levers I43 and, hence, thevariation of the distance between the pins hi are of minor importanceand not apt to cause a measurable angular displacement of the eccentricI90 relatively to the pins I41 connected to the bevel gear I28.

From the foregoing, it is believed that the construction and advantagesof the present invention ma be readily understood by those skilled inthe art without further description, it being borne in mind thatnumerous changes may be made in the details disclosed without departingfrom the spirit of the invention as set out in the following claims.

What is claimed and desired to be secured by Letters Patent is:

1. A driving conn ction adapted to operate at least one rectilinearlyreciprocable member by means of a rotatable shaft, comprising incombination an inner eccentric fast on said shaft, an outer eccentricrotatably supported on said inner eccentric and having an eccentricityequal to the eccentricity of said inner eccentric, a ring memberrotatably supported by said outer eccentric and coupled to saidreciprocable member for reciprocating therewith, guiding means forpreventing rotation of the said ring member relatively to the axis ofreciprocation of the reciprocable member, a driving member rotatableabout the axis of said shaft, a coupling between said driving member andsaid outer eccentric serving to constrain them to rotate at equalangular velocities, while permitting displacement of the eccentric indirections transverse to the axis of rotation, and driving connectionsbetween said shaft and said driving member for rotating the latter atthe same angular velocity as said shaft and in the opposite direction.

2. A driving connection adapted to operate at least one rectilinearlyreciprocable member by means of a rotatable shaft, comprising incombination an inner eccentric fast on said shaft, an outer eccentricrotatably supported on said inner eccentric and having an eccentricityequal to the eccentricit of said inner eccentric, a ring memberrotatably supported by said outer eccentric and coupled to saidreciprocable member for reciprocating therewith, guiding means forpreventing rotation of said ring member relative to the axis ofreciprocation of the reciprocable member, driving member rotatable aboutthe axis of said shaft, an Oldham coupling connecting said drivingmember with said outer eccentric, and driving connections between saidshaft and driving member for rotating said driving member at the sameangular velocity as said shaft and in the opposite direction.

3. A driving connection adapted to operate at least one rectilinearlyreciprocable member by means of a rotatable shaft, comprising incombination an inner eccentric fast on said shaft, an outer eccentricrotatably supported on said inner eccentric and having an eccentricityequal to the eccentricity of said inner eccentric, a ring memberrotatably supported by said outer eccentric and coupled to saidreciprocable member for reciprocating therewith, guiding means forpreventing rotation of the said ring member relative to the axis ofreciprocation of the reciprocable member, a driving member rotatableabout the axis of said shaft, a pair of rocking levers pivoted to theouter eccentric and meshing with one another to effect equally opposedrocking movements relative to said outer eccentric, two steering barsconnected each to one of said rocking levers and pivoted to the saiddriving member so as to couple said outer eccentric for rotation withsaid driving member, and driving connections between said shaft anddriving member for rotating said driving member at the same angularvelocity as said shaft and in the opposite direction.

I-IESPER VON TAVEL.

